[Abstract not provided by PI] SPECIFIC AIMS In normotensive African-Americans, we will determine: 7 Whether the phenomenon of salt-sensitivity is or is not evoked in normotensive blacks, depending on whether the dietary intake of potassium is marginally deficient or high-normal, respectively. 7 Whether the phenomenon of normotensive salt-sensitivity is associated with a renal hemodynamic derangement that is characterized by an increased filtration fraction and whether that increase is prevented when a high-normal dietary intake of potassium prevents expression of salt-sensitivity. 7 Whether in those who are salt-sensitive: a) dietary loading of sodium citrate elicits either a pressor response or renal hemodynamic derangement; and b) dietary loading of Cl- as KCl augments any part of the renal hemodynamic derangement induced by NaCl loading. 7 Whether sympathetic stress augments either salt-sensitivity or any part of the associated renal hemodynamic arrangement, and whether dietary potassium modulates any such augmentation.. 7 Whether in those who are salt-sensitive, dietary potassium modulates salt-induced microalbuminuria.